Aerial or aerial system



June'9,1942. E; c, @Rg E 2,285,395

mam. onmnm sysqrsm Filed Nov. '29, 1959 2 Sheets-Sheet 1 INVENTO EDWARD CECIL C OiK "/85 Y ATTORNEY JOSEPH LA BY I MM June 9, 1942. I E. c. coRK El'AL 2,285,395

AERIAL 0R AERIAL SYSTEM I Filed Nov. 29, 1939 I 2 Sheets-Sheet 2 INVENTORS gQSEP/I LADEPAWSE'Y I ATTORNEY Patented June 9, 1942 AERIAL OR AERIAL SYSTEM Edward Cecil Cork, Ealing,

Lade Pawsey,

London, and Joseph Ickenham, England, assignors to Electric & Musical Industries Limited, Hayes, Middlesex, England, a company of Great Britain Application November 29, 1939, Serial No. 306,594 In Great Britain December 19, 1938 13 Claims.

The present invention relates to aerials and aerial systems for radio transmitters or receivers and is more especially but not exclusively applicable to aerials or aerial systems for use in the transmission and reception of signals in the so-called ultra-short wave bands, for example, such as are used in television signal transmis- 51011.

In the specification of our co-pending patent application No. 279,244, filed June 15, 1939, aerials or aerial systems are described comprising a single tubular shell or a plurality of shells or a conductor system equivalent to a tubular shell or shells surrounding a metal mast. These aerials or aerial systems are primarily intended for use on ships and in installing them, in some cases, difiiculties have been experienced owing to the necessity of providing space for ladders to afford passage-way up and down the mast.

The object of the present invention is to provide an aerial or aerial system for ultra-short wave working which may be mounted on a single metal mast in such manner as to be capable of radiating signals in all directions horizontally at useful strength, and to allow for the accommodation of ladders or other obstruction on the mast in the vicinity of the aerial or aerial system.

According to the present invention an aerial system for transmitting or receiving signals over a wide band of frequencies is provided comprising a pair or pairs of radiating elements mounted on an electrically conducting mast, the units of each pair being disposed about the mast on opposite sides thereof and each element presenting a large area in a direction perpendicular to a diametral plane through the mast.

In a preferred form of the invention an aerial system for transmitting or receiving signals over a wide band of frequencies is provided comprising a pair or pairs of oppositely disposed radiating elements mounted on an electrically conducting mast which also serves as a radiator, the spacing of each element from the mast and the diameter of the mast being small compared with said wave length and the transverse dimensions of the elements being large relative to said spacing, the arrangement being such that in operation the aerial system has a circular or nearly circular radiation diagram in a plane perpendicular to the axis of the mast in respect of signals in said band of frequencies.

The nature of the invention and the method of carrying the invention into eifect will be fully understood from the following description of a specific example with reference to the accompanying drawings of which- Figure 1 is a side elevational view of an aerial system according to the invention and its supporting mast.

Figure 2 is a plan View in section through the line IIII of Figure 1, and

Figure 3 is a graph showing the directional characteristics of the radiation obtained using an aerial as shown in the preceding figures.

Referring to Figures 1 and 2, and more especially to Figure 1, it will be seen that the aerial is supported on a tubular steel mast l, which has mounted on it four collars 2 from each of which project four structures 3 which each constitute a quarter wave earthing bar. The separation between each of the two uppermost and the two lowermost collars 2 is one quarter wave length and the separation between the intermediate pair of collars 2 is somewhat greater than one half wave length.

Supported between adjacent pairs of the intermediate earthing bar structure 3 are upper and lower sets 5 and 6 of aerial conductors each approximately one eighth of a wave length long and each set comprising five conductors 5a or 6a (see Figure 1), assembled between pairs of cross-bars 5b and 6b in such manner that each set forms a rectangular mat-like structure simulating a continuous conductive surface. The upper cross-bars 5b of aerials 5 are each suspended from a rod 50 supported on an adjacent pair of the upper intermediate earthing bar structure 3 by means of insulated suspension wires 501 provided with egg insulators 5e, whilst the lower cross-bars'5b of aerials 5 are supported on brackets 1 extending from clamping ring la secured on the mast, the length of suspension wires 5d and the position of clamping ring la' being such that the conductors 5a are held under sufiicient tension to maintain them extended.

The upper cross-bars 6b of aerials 6 are carried on brackets 8 extending from a clamping ring 8a similar to the arms 1 and ring la provided for the lower bars 5b, and the lower cross-bars 6b are connected to rods 50 by insulated wires 602 having egg insulators 6e similar to the wires 5d and insulators 5e by which the aerials 5 are suspended, aerial conductors to being also maintained under sufiicient tension to keep them extended.

The lower ends of aerial conductors 5a and the upper ends of aerial conductors to are connected to branches 9a, and 9b respectively of quarter wave length feeders 9 of the concentric conductor type which extend one up each side of the mast I from a common feeder it, each branch 9a and 9b being one quarter of a wavelength long and only the branch 90. being provided with a core. The connections of the feeders 9 to the aerials 5 and 6 respectively, is effected at the anchorages afiorded by insulators ll provided on the mast as shown in Figure 1, the method of connection being as illustrated in Figure 2 of United States Patent No. 2,127,088, granted August 15, 1938, to W. S. Percival et, al., whereby transmission of current down the outside of either feeder 9 is prevented.

The aerials 5 and 6 are supported at a distance of approximately one tenth of a Wave length from the mast l, the gap such as l2 in Figure 1 between each aerial 5 and the corresponding aerial 6 being approximately one eighth of a wave length, and the distance between the outer conductors 5a or 6a as the case may be, being slightly greater than the diameter of mast I, and such that outer parts of the aerial mats 5 and 6 are located at a distance of an eighth of wavelength from the mast I.

With the above arrangement voltage antinodes tend to be set up in the region of the intermediate collars but are substantially suppressed due to the earthing effect of the structures 3. Similarly the potential fluctuations in the vicinity of the upper and lower collars Z are suppressed and transmission of energy along the mast beyond these collars is substantially prevented.

As the distance between mast l and aerials 5 and 6 is about one tenth of a wave length and the aerials are plane and symmetrically disposed about the mast, the side elements 5a and 6a of the aerials 5 and 6 will be spaced from the mast l by approximately one eighth of a wave length, so that, owing to the reflective eifect of the mast I, the radiation from the side elements of each aerial 5 or 6 is a maximum. Effective radiation also takes place from the part of the mast 1 between the rings la and 8a. The net result is to give a horizontal radiation diagram for the aerial system shown of the form indicated by the curve H in Figure 3. In this figure the horizontal axis Oh corresponds with the direction indicated by arrow IS in Figure 2.

A typical vertical radiation characteristic is shown by the curve V having lobes V1 and V2.

With the arrangement described above ladders may be arranged at either side of the mast, for example, at I5 or 16 (see Figure 2) without interfering with the aerial structure in any way.

As will be seen from Figures 1 and 2 the structures 3 each consist of three rods 3a. radiating from the associated collar 2, the rods 30. being joined at their tips to form an elongated triangular pyramid shape structure. There is arranged in the tips of each pyramid structure 3 a conducting rod (not shown), for example, of brass, which may be screwed or slid in or out to adjust the effective length of the structure 3 to secure the most effective earthing of the mast thereby. A structure such as 3 may also be used for other purposes besides earthing.

Figures 1 and 2 are drawings approximately to scale of a specific form of the invention in which the diameter of the mast I is one foot and the radiation frequency of the aerial is 75 megacycles.

It will be appreciated that the scope of the invention is not restricted to the details of con-. struction shown in the drawings. For example,

aerials 5 or 6 may be formed of continuous conductive sheets or gauze. Moreover, different forms of earthing bars 3 may be used.

We claim:

1. An aerial system for transmitting or receiving signals over a wide band of frequencies, said systems comprising one or more pairs of radiating elements mounted on an electrically conducting mast, the elements of each pair being disposed about the mast on opposite sides thereof and each .element comprising a plurality of parallel co-planar conductors, said conductors being conductively connected at each end, the length of said conductors being of the order of an eighth of the mean operating Wavelength.

2. An aerial system for transmitting or receiving signals over a wide band of frequencies, said systems comprising one or more pairs of radiating elements mounted on an electrically conducting mast, the elements of each pair being disposed about the mast on opposite sides thereof and each element comprising a plurality of parallel co-planar conductors, said conductors being conductively connected at each end, the length of said conductors being of the order of an eighth of the mean operating wavelength and means for energizing said element connected to one end thereof, said mast being effectively earthed at points located at distances of a quarter and a half of the mean operating wavelength above and below the level of the connection of said energizing means.

3. An aerial system for transmitting o-r receiving signals over a wide band of frequencies, said system comprising one or more pairs of dipole radiators mounted on an electrically conducting mast, the dipoles of each pair being disposed about the mast on opposite sides thereof and each dipole comprising a pair of groups of parallel co-planar conductors, the conductors of one group being arranged in an end-on relationship with respect to the conductors of the other group, the conductors of each group being conductively connected ateach end, the length of said conductors being of the order of an eighth of the mean operating wavelength.

4. An aerial system for transmitting or receiving signals over a wide band of frequencies, said system comprising one or more pairs of dipole radiators mounted on an electrically conducting mast and parallel thereto, the dipoles of each pair being disposed about the mast on opposite sides thereof and each dipole comprising a pair of groups of parallel co-planar conductors, the conductors of one group being co-linearly arranged with respect to the conductors of the other group, the conductors of each group being conductively connected at each end, the length of said conductors being of the order of an eighth of the mean operating wavelength and means for energizing said radiator connected to adjacent ends of said groups of conductors.

5. An aerial system for transmitting or receiving signals over a wide band of frequencies, said system comprising one or more pairs of oppositely disposed radiating elements mounted on an electrically conducting mast which also serves as a radiator, the spacing of each element from the mast and the diameter of the mast being substantially less than a quarter of the mean operating wavelength and the transverse dimensions of said elements being of the order of said spacing, each of said elements comprising a plurality of parallel co-planar conductors, said conductors being conductively connected at each end.

the length of said conductors being of the order of an eighth of the mean operating wavelength.

6. An aerial system for transmitting or receiving signals over a wide band of frequencies, said system comprising one or more pairs of oppositely disposed radiating elements mounted on an electrically conducting mast which also serves as a radiator, each of said elements comprising a plurality of parallel co-planar conductors, said conductors being conductively connected at each end, the length of said conductors, the spacing of each element from the mast, the diameter of the mast and the transverse dimensions of said elements being of the order of an eighth of the mean operating wavelength and means for energizing each of said elements connected to one end thereof.

7. An aerial system for transmitting or receiving signals over a wide band of frequencies, said system comprising one or more pairs of ppositely disposed dipole radiators mounted parallel to an electrically conducting mast which also serves as a radiator, each of said dipole radiators comprising a pair of groups of parallel co-planar conductors, the conductors of one group being co-linearly arranged with respect to the conductors of the other group, the conductors of each group being conductively connected at each end, the length of said conductors, the spacing of each element from the mast, the diameter of the mast and the transverse dimensions of said dipole radiators being substantially of the order of an eighth of the mean operating wavelength.

8. An aerial system for transmitting or receiving signals over a wide band of frequencies, said system comprising one or more pairs of oppositely disposed dipole radiators mounted parallel to an electrically conducting mast which also serves as a radiator, the spacing of each element from the mast and the diameter of the mast being of the order of an eighth of the mean operating wavelength and the transverse dimensions of said dipole radiators being substantially of the order of said spacing, each of said dipole radiators comprising a pair of groups of parallel co-planar conductors, the conductors of one group being co-linearly arranged with respect to the conductors of the other group, the conductors of each group being conductively connected at each end and means for energizing each of said radiators connected to adjacent ends of the groups of conductors of each radiator, said mast being effectively earthed at points located at distances of a quarter and a half of the mean operating wavelength above and below the level of the connection of said energizing means.

9. An aerial system for transmitting or receiving signals over a wide band of frequencies, said system comprising one or more pairs of oppositely disposed radiating elements mounted on an electrically conducting mast which also serves as a radiator, the spacing of each element from the mast and the diameter of the mast being substantially less than a quarter of the mean operating wavelength and the transverse dimensions of said elements being of the order of said spacing, each of said elements comprising a plurality of parallel co-planar conductors, said conductors being conductively connected at each end.

10. An aerial system for transmitting or receiving signals over a wide band of frequencies, said system comprising one or more pairs of oppositely disposed radiating elements mounted on an electrically conducting mast which also serves as a radiator, the spacing of each element from the mast and the diameter of the mast being small compared to the wavelength at the mid-frequency of said band and the transverse dimensions of said elements being of the order of said spacing, each of said elements comprising a plurality of parallel co-planar conductors, said conductors being conductively connected at each end.

11. An aerial system for transmitting or receiving signals over a wide band of frequencies, said system comprising one or more pairs of oppositely disposed dipole radiators mounted parallel to an electrically conducting mast which also serves as a radiator, each of said dipole radiators comprising a pair of groups of parallel co-planar conductors, the conductors of one group being colinearly arranged with respect to the conductors of the other group, the conductors of each group being conductively connected at each end, the length of said conductors, the spacing of each element from the mast, the diameter of the mast and the transverse dimensions of said dipole radiators being small compared to the wavelength at the mid-frequency of said band.

12. An aerial system for transmitting or receiving signals over a wide band of frequencies, said system comprising one or more pairs of oppositely disposed dipole radiators mountedparallel to an electrically conducting mast which also serves as a radiator, the spacing of each element from the mast and the diameter of the mast being small compared to the wavelength at the mid-frequency of said band and the transserve dimensions of said dipole radiators being substantially of the order of said spacing, each of said dipole radiators comprising a pair of groups of parallel co-planar conductors, the conductors of one group being co-linearly arranged with respect to the conductors of the other group, the conductors of each group being conductively connected at each end and means for energizing each of said radiators connected to adjacent ends of the groups of conductors of each radiator.

13. An aerial system for transmitting or receiving signals over a wide band of frequencies, said system comprising one or more pairs of oppositely disposed dipole radiators mounted parallel to an electrically conducting mast which also serves as a radiator, the spacing of each element from the mast and the diameter of the mast being small compared to the wavelength at the mid-frequency of said band and the transverse dimensions of said dipole radiators being substantially of the order of said spacing, each of said dipole radiators comprising a pair of groups of parallel co-planar conductors, the conductors of one group being co-linearly arranged with respect to the conductors of the other group, the conductors of each group being conductively connected at each end and means for energizing each of said radiators connected to adjacent ends of the groups of conductors of each radiator,

said mast being effectively earthed at points located at distances of a quarter and a half of the means operating wavelength above and below the level of the connection of said energizing means.

EDWARD CECIL CORK. JOSEPH LADE PAWSEY. 

